Using the notations from [1]}, we write
\(\mathcal {A}^{\mathrm {ind}}\)  for the closure of \(\mathcal {A}\)  under taking
vertex-induced subgraphs, and \(K_2 + K_2\) , \(P_4\)  and \(L_4\)  refer to the graphs
shown in fig:excluded. We also write \(K_2\)  for the complete graph on 2
vertices.
<FIGURE>